Audi A7 Cooling System Mystery Causing Engine Issues

I had a very similar issue with my 2014 Audi A6 diesel last winter. Being somewhat experienced with basic car maintenance, I initially thought the radiator grille or restricted airflow might be the problem, but it turned out to be much simpler. The workshop diagnosed a faulty fuse controlling the cooling system sensors, which was causing erratic temperature readings and affecting the thermal management system. The restricted airflow and radiator blockage I suspected weren't actually the problem at all. The repair was straightforward, they replaced the blown fuse and ran a diagnostic check to ensure all sensors were functioning correctly. Total cost was 52 Euro including the diagnostic fee. To provide more specific advice for your A7, could you share: Current mileage, Any recent maintenance work, Whether you notice any coolant leaks, If the check engine light shows any specific error codes, Whether the heating system is working normally These details would help determine if your issue matches what I experienced or might be something different.

I had a very similar issue with my 2014 Audi A6 diesel last winter. Being somewhat experienced with basic car maintenance, I initially thought the radiator grille or restricted airflow might be the problem, but it turned out to be much simpler. The workshop diagnosed a faulty fuse controlling the cooling system sensors, which was causing erratic temperature readings and affecting the thermal management system. The restricted airflow and radiator blockage I suspected weren't actually the problem at all. The repair was straightforward, they replaced the blown fuse and ran a diagnostic check to ensure all sensors were functioning correctly. Total cost was 52 Euro including the diagnostic fee. To provide more specific advice for your A7, could you share: Current mileage, Any recent maintenance work, Whether you notice any coolant leaks, If the check engine light shows any specific error codes, Whether the heating system is working normally These details would help determine if your issue matches what I experienced or might be something different.

I had a very similar issue with my 2014 Audi A6 diesel last winter. Being somewhat experienced with basic car maintenance, I initially thought the radiator grille or restricted airflow might be the problem, but it turned out to be much simpler. The workshop diagnosed a faulty fuse controlling the cooling system sensors, which was causing erratic temperature readings and affecting the thermal management system. The restricted airflow and radiator blockage I suspected weren't actually the problem at all. The repair was straightforward, they replaced the blown fuse and ran a diagnostic check to ensure all sensors were functioning correctly. Total cost was 52 Euro including the diagnostic fee. To provide more specific advice for your A7, could you share: Current mileage, Any recent maintenance work, Whether you notice any coolant leaks, If the check engine light shows any specific error codes, Whether the heating system is working normally These details would help determine if your issue matches what I experienced or might be something different.

Latest service was done at 197000 KM, now at 198047 KM. Thanks for sharing your experience with the fuse issue. I checked for coolant leaks as suggested and found none. The heating system works fine, but I noticed the engine overheating warning appears intermittently, especially during highway driving. Got the error codes read: P0115 and P0128 showing up. From what I understand, these relate to engine coolant temperature sensor circuit problems. This seems to align with your sensor-related experience rather than a mechanical cooling system problem. Will have it checked at a workshop this week. Really helps knowing about your similar case, saves time ruling out the radiator grille issues I initially suspected.

Latest service was done at 197000 KM, now at 198047 KM. Thanks for sharing your experience with the fuse issue. I checked for coolant leaks as suggested and found none. The heating system works fine, but I noticed the engine overheating warning appears intermittently, especially during highway driving. Got the error codes read: P0115 and P0128 showing up. From what I understand, these relate to engine coolant temperature sensor circuit problems. This seems to align with your sensor-related experience rather than a mechanical cooling system problem. Will have it checked at a workshop this week. Really helps knowing about your similar case, saves time ruling out the radiator grille issues I initially suspected.

Latest service was done at 197000 KM, now at 198047 KM. Thanks for sharing your experience with the fuse issue. I checked for coolant leaks as suggested and found none. The heating system works fine, but I noticed the engine overheating warning appears intermittently, especially during highway driving. Got the error codes read: P0115 and P0128 showing up. From what I understand, these relate to engine coolant temperature sensor circuit problems. This seems to align with your sensor-related experience rather than a mechanical cooling system problem. Will have it checked at a workshop this week. Really helps knowing about your similar case, saves time ruling out the radiator grille issues I initially suspected.

Thanks for providing those details. Yes, those error codes definitely match what I experienced with my A6. The P0115 and P0128 codes are classic indicators of coolant temperature sensor issues, which explains the inconsistent temperature readings and engine overheating warnings. In my case, after the initial fuse replacement, we discovered the wiring harness connecting to the coolant temperature sensor had some corrosion. The total repair ended up costing 180 Euro, including replacing the sensor and harness. While more expensive than just a fuse, it completely resolved the engine overheating warnings and erratic temperature displays. The timing is interesting, these sensor issues often show up around the 190000-200000 KM mark in these engines. The radiator blockage or cooling grille restrictions we initially suspected would typically show different symptoms, like consistent rather than intermittent overheating. Since your mileage is similar to when I had the problem, and the error codes match, you might want to have the workshop check the sensor wiring harness specifically. It saved me a second trip when I mentioned this to my mechanic.

Thanks for providing those details. Yes, those error codes definitely match what I experienced with my A6. The P0115 and P0128 codes are classic indicators of coolant temperature sensor issues, which explains the inconsistent temperature readings and engine overheating warnings. In my case, after the initial fuse replacement, we discovered the wiring harness connecting to the coolant temperature sensor had some corrosion. The total repair ended up costing 180 Euro, including replacing the sensor and harness. While more expensive than just a fuse, it completely resolved the engine overheating warnings and erratic temperature displays. The timing is interesting, these sensor issues often show up around the 190000-200000 KM mark in these engines. The radiator blockage or cooling grille restrictions we initially suspected would typically show different symptoms, like consistent rather than intermittent overheating. Since your mileage is similar to when I had the problem, and the error codes match, you might want to have the workshop check the sensor wiring harness specifically. It saved me a second trip when I mentioned this to my mechanic.

Thanks for providing those details. Yes, those error codes definitely match what I experienced with my A6. The P0115 and P0128 codes are classic indicators of coolant temperature sensor issues, which explains the inconsistent temperature readings and engine overheating warnings. In my case, after the initial fuse replacement, we discovered the wiring harness connecting to the coolant temperature sensor had some corrosion. The total repair ended up costing 180 Euro, including replacing the sensor and harness. While more expensive than just a fuse, it completely resolved the engine overheating warnings and erratic temperature displays. The timing is interesting, these sensor issues often show up around the 190000-200000 KM mark in these engines. The radiator blockage or cooling grille restrictions we initially suspected would typically show different symptoms, like consistent rather than intermittent overheating. Since your mileage is similar to when I had the problem, and the error codes match, you might want to have the workshop check the sensor wiring harness specifically. It saved me a second trip when I mentioned this to my mechanic.

I appreciate the detailed response and guidance. The workshop completed their inspection today and confirmed exactly what you described, corroded wiring to the coolant temperature sensor was causing the automotive cooling system issues. Total repair came to 195 Euro, slightly more than your case but included a full system diagnostic check. The mechanic showed me the old wiring harness and it was clearly degraded. They replaced both the sensor and harness assembly. They also performed a cooling system pressure test to verify no other engine cooling issues were present. Car has been running perfectly for the past 200km, no more engine overheating warnings or erratic temperature readings. The check engine light is now off and warm-up time is back to normal. Really glad we identified this as a sensor issue rather than a mechanical problem with the radiator or grille that I initially suspected. Your shared experience helped me communicate the likely issue to the workshop, which definitely streamlined their diagnostic process. Great to have a quick, targeted fix rather than replacing components unnecessarily.

I appreciate the detailed response and guidance. The workshop completed their inspection today and confirmed exactly what you described, corroded wiring to the coolant temperature sensor was causing the automotive cooling system issues. Total repair came to 195 Euro, slightly more than your case but included a full system diagnostic check. The mechanic showed me the old wiring harness and it was clearly degraded. They replaced both the sensor and harness assembly. They also performed a cooling system pressure test to verify no other engine cooling issues were present. Car has been running perfectly for the past 200km, no more engine overheating warnings or erratic temperature readings. The check engine light is now off and warm-up time is back to normal. Really glad we identified this as a sensor issue rather than a mechanical problem with the radiator or grille that I initially suspected. Your shared experience helped me communicate the likely issue to the workshop, which definitely streamlined their diagnostic process. Great to have a quick, targeted fix rather than replacing components unnecessarily.

I appreciate the detailed response and guidance. The workshop completed their inspection today and confirmed exactly what you described, corroded wiring to the coolant temperature sensor was causing the automotive cooling system issues. Total repair came to 195 Euro, slightly more than your case but included a full system diagnostic check. The mechanic showed me the old wiring harness and it was clearly degraded. They replaced both the sensor and harness assembly. They also performed a cooling system pressure test to verify no other engine cooling issues were present. Car has been running perfectly for the past 200km, no more engine overheating warnings or erratic temperature readings. The check engine light is now off and warm-up time is back to normal. Really glad we identified this as a sensor issue rather than a mechanical problem with the radiator or grille that I initially suspected. Your shared experience helped me communicate the likely issue to the workshop, which definitely streamlined their diagnostic process. Great to have a quick, targeted fix rather than replacing components unnecessarily.